Outer Limits 4x4 Board

do u need duel batterys to run a fridge? im only lookin at an engle 40ltr how long wil it run for befor the battery is dead? it is a 91 4runner

Dependds on a few things.

How big is your battery?

How old is it?

Where are you going to be using it?? QLD? TAS? Very different.


Jimmy

Its a good idea to run a second battery for a fridge. The first time your fridge runs your single battery down past that point that it will crank your engine over in the morning, is the time you will kick yourself for not having one fitted. And you will be kicking yourself harder if its an auto, or somewhere where push starting isnt possible, or your alone without jumper leads.

BundyRumandCoke wrote:Its a good idea to run a second battery for a fridge..

x 22....

Too many variables to say how long a battery will last, but you dont want to find out while your on your own eleventy hours from home...

"The first time your fridge runs your single battery down past that point that it will crank your engine over in the morning, is the time you will kick yourself for not having one fitted."

Agree

If you dont want to set up a duel battery system i would consider buying one of those jump start packs just incase. In my surf i used to run the fridge in the car while i was driving and for a couple of hours while we were stopped and i would then let the fridge run off the pack itself!! But i was generally in cold Vic weather!! Or you could just run it off your car and use the jump starter in the morning if needed! Or get a battery box and buy a second battery and charge it using anderson plugs. Saves up some engine bay space.

During winter my 40lt will run for 2days n nights before the single battery is flat.
During summer my 40lt will go for about 24hrs before I can`t start the 80. My brothers 60lt (which I have atm) will go for about 15hrs before it will not start.

All those are if everything is 100% with the electrical system.

I run the fridge 24/7 as I use it for drinks for work. During the day while on job sites it just runs off the battery, sometimes I`ll run a lead to the car if power is close by. Of a night time I just back the 80 in the shed and plug the fridge into 240v for over night.

Biggest problem with running a fridge off one battery is the amount of draw it has verses the amount of charging time the battery has. Most of the time you don`t drive your car long enough to fully replace the charge the fridge as drawn and over time (might be 2 weeks) you`ll end up with a flat battery.

I only have a single battery in my GU and run a Waeco 40ltr on camping trips without to many dramas. i do need to monitor it but haven't been caught out yet. You have to be a bit more diligent with your packing of the fridge, don't open it all the time, make sure it is running efficiently. I make sure I park in the shade where possible, use the insulated bag, have shade screens etc on the windows. I do however have a Waeco Coolpower battery pack as a back up and will be using this more when we spend a few days at a time when camping away from power sources.

u could buy one of those fridges that runs for 3 weeks off a 9kg bottle of gas.....
u wont have to buy a second battery then....
anyone had any experience with them?

The Waeco says it has a safety cutout for your battery.(10.5Volts i think)
has anyone had experience with these??

DIRTY ROCK STAR wrote:The Waeco says it has a safety cutout for your battery.(10.5Volts i think)
has anyone had experience with these??

I think so, ours went into a mode where we couldn't seem to get things nice and icy cold. it had switched to a setting that we had to reset back to normal, if that makes any sense.

The fridges I have used (Engel, Explorer) have a cut out at about 10.5v, which is when the fridge stops drawing from the battery in theory so you can still start your car. This works to some extent depending on how hard your car is to crank over, most diesels need more then 10.5. Also as stated above some fridges don't always restart nicely when the voltage in the battery rises above 10.5 and the fridge has to be re set/restarted.

As well regularly drawing your battery down as low as 10.5 won't do it a lot of good.

So duals is the way to go

Matt

Here,s a drawing I did for the father in law,He has a troopy and runs two fridges,Cheers Paul.

I have often ran my 39l engel overnight on a single battery with out a problem. But i wouldn't recommend it.

my battery is 700cca its a good 4wd one do u have to run to the same or can u run one smaller loke a 300cca

MART wrote:Here,s a drawing I did for the father in law,He has a troopy and runs two fridges,Cheers Paul.

you could achieve the same effect with a single relay...

but

when the engine is running, the battery isolator should connect the batteries in parallel, in effect undoing what you have tried to achieve. Put another way, with the engine running, the batteries are a LOAD, not a SOURCE - the alternator is the power source, and it is running the fridge(s) AND charging the batteries. Unless I have completely misunderstood what you have tried to achieve, I don't see the point of it.



anyway to answer the original question, go duals, they are cheap and easy to set up especially if you have the skillz to fab up the mounting for the second battery, a solenoid isolator is all that is really necessary to make it work so you can get out of it for the cost of a battery plus $50 for wire and stuff, pretty cheap since you're prepared to pay the price of the fridge in the first place. there are other advantages to having a second battery, it is easy to set up some lights, and run TV/DVD/computer and that sort of stuff if that's the kind of camping you're into.

cheers

DD

I think you are not reading the drawing properly,when the car is parked the fridges run of the reserve,both,when driving both fridges run of the main,this allows reserve battery to charge fullywith no load, I am not using standard relays,Cheers Paul.

P.S. Two trips to cape york,2 years apart,2 fridges,never a flat battery.

I put a deep cycle 90Ah caravan battery in my second tray and it has its own circuit/fusebox that feeds some plugs/fridge at the back and the uhf. Off the shelf relay between it and the alternator means it is easy to fix and there is no mystery to any system if something plays up.

Get up to 3 days without driving (not using it for beers) and more if I put a frozen cryo'd roast in the bottom of my 40l engel, been away for up to 2 weeks it's been all good. I chuck the multimeter on it every day and if it's near 11 I go for a wheel, 30 mins charges it up heaps often enough for 2 more days with the 2H alternator.

Never tried to run it off a cca style battery, it'd suck especially if you had beers in it and opened it all the time, perhaps on a fresh battery I'd be confident but otherwise :)

I've got an 800cca truck/4wd battery in my car and run my fridge off that. Fully or close to fully charged it lasts all night without a hassle.... then 2nd night camping is a different story as my alternator is crap and I need a good long drive to charge up the battery

BundyRumandCoke wrote:The first time your fridge runs your single battery down past that point that it will crank your engine over in the morning...

...will be the day after the RACQ contractor on North Stradbroke Island finished.

Never again!

That was my biggest problem when I originally set up my truck with duals.
I used 2 x 6v trojans as my second bank to give me massive a/hours which is good in some ways but bad in others. not to mention costs!!!

You could stay in one place for a long time running a 80l waeco plus lights, etc but then once the batteries did go down the alternator had no hope of recovering the charge fully in the batteries. The big deep cycles last for a long time but don't accept charge from the alternator well. They need a proper 3/4 stage 240v charger to charge fully

Next time I think I will run a dual purpose type battery so while it will run out of charge quicker, a quick run in the vehicle will pump plenty of charge back in to the battery.

Back to main topic, I think if you are going to spend money on a fridge then take some stress off when camping and go duals. The time you regret not doing it will suck bad!!!